OnlineCBT
Physics · LAWS OF MOTION
Practice questions & answers
Find a question, read its answer and explanation, then practise related questions.
Physics LAWS OF MOTION · Clear filters
120 questions
Physics · LAWS OF MOTION
Match List-I with List-II: List-I List-II A Static friction \( f_s \) I \( \mu_k N \), opposes relative sliding motion B Kinetic friction \( f_k \) II Equal to total change in linear momentum C Restoring force in spring III Self-adjusting force up to a limiting maximum value D Impulse IV \( -kx \), directed opposite to displacement Choose the correct answer from the options given below:
Read answer →Physics · LAWS OF MOTION
Two bodies of masses \( m_1 = 2 \text{ kg} \) and \( m_2 = 8 \text{ kg} \) are initially at rest. Equal forces \( F_1 \) and \( F_2 \) act on them for time intervals \( \Delta t_1 \) and \( \Delta t_2 \) respectively. If both bodies acquire the same final linear momentum, the ratio of time intervals \( \Delta t_1 / \Delta t_2 \) is:
Read answer →Physics · LAWS OF MOTION
A block of mass \( 3\text{ kg} \) is suspended vertically by a string connected over a frictionless pulley to a trolley of mass \( 20\text{ kg} \) resting on a horizontal track. If coefficient of kinetic friction between trolley and surface is \( 0.04 \), find acceleration of system. (Take \( g = 10\text{ m s}^{-2} \))
Read answer →Physics · LAWS OF MOTION
A gun of mass \( M \) fires a bullet of mass \( m \) with a muzzle velocity \( v \) relative to the gun barrel. Assuming the system is initially at rest on a smooth horizontal surface, the recoil speed of the gun relative to the ground is:
Read answer →Physics · LAWS OF MOTION
A block of mass \( m \) is pressed against a rough vertical wall by applying a horizontal force \( F \). If the coefficient of static friction between the wall and the block is \( \mu_s \), the minimum magnitude of horizontal force \( F \) required to prevent the block from slipping downwards is:
Read answer →Physics · LAWS OF MOTION
A ball is released from rest from a height \( h = 0.8 \text{ m} \) on a smooth inclined plane. It then rolls onto a horizontal surface with a coefficient of kinetic friction \( \mu = 0.2 \). What is the distance \( s \) travelled by the ball on the horizontal plane before coming to rest?
Read answer →Physics · LAWS OF MOTION
A block of mass \( m = 4\text{ kg} \) is placed on top of another block of mass \( M = 6\text{ kg} \), which rests on a smooth horizontal floor. The coefficient of static friction between the upper and lower blocks is \( \mu_s = 0.3 \). Taking \( g = 10\text{ m/s}^2 \), calculate the maximum horizontal force \( F_{\max} \) that can be applied to the lower block \( M \) such that both blocks accelerate together without relative slipping.
Read answer →Physics · LAWS OF MOTION
A circular racetrack of radius \( R = 100\text{ m} \) is banked at an angle of \( \theta = 45^\circ \). The coefficient of static friction between the race-car tyres and the track is \( \mu_s = 0.5 \). Taking \( g = 10\text{ m/s}^2 \), find the ratio of the maximum permissible speed \( v_{\max} \) (to avoid slipping outwards) to the optimum speed \( v_0 \) (where no frictional force is required).
Read answer →Physics · LAWS OF MOTION
A block of mass \( m = 4\text{ kg} \) rests on a rough horizontal surface with coefficient of static friction \( \mu_s = 0.5 \). A light string connected to the block passes over a smooth frictionless pulley and supports a hanging block of mass \( m_0 \). What is the maximum value of \( m_0 \) for which the system remains at rest?
Read answer →Physics · LAWS OF MOTION
In SI units, force is defined using the formula \( F = k m a \). The value of the proportionality constant \( k \) is set to 1 because:
Read answer →Physics · LAWS OF MOTION
A rubber ball of mass \( 0.25 \text{ kg} \) strikes a vertical rigid wall horizontally with a speed of \( 10 \text{ m s}^{-1} \) and rebounds along the same path with the same speed. The magnitude of impulse delivered by the wall to the ball is:
Read answer →Physics · LAWS OF MOTION
A car negotiates a level, unbanked circular turn of radius \( R = 40\text{ m} \). The coefficient of static friction between the tyres and the road is \( \mu_s = 0.25 \). Taking \( g = 10\text{ m/s}^2 \), calculate the maximum safe speed \( v_{\max} \) to avoid slipping. If the speed of the car is increased to \( 15\text{ m/s} \), determine the new minimum coefficient of static friction \( \mu_s' \) required to prevent the car from slipping.
Read answer →Physics · LAWS OF MOTION
Match List-I with List-II: List-I List-II A Linear Momentum I \( \text{kg m s}^{-1} \) B Newton's Second Law II \( \vec{F} = \frac{d\vec{p}}{dt} \) C Impulse III \( \int \vec{F} dt \) D Newton's First Law IV \( \vec{F}_{\text{net}} = 0 \implies \vec{a} = 0 \) Choose the correct answer from the options given below:
Read answer →Physics · LAWS OF MOTION
A constant net force \( \vec{F} = (10 \hat{i} - 6 \hat{j} + 8 \hat{k})\text{ N} \) produces an acceleration of magnitude \( 5\sqrt{2}\text{ m/s}^2 \) in a body. The mass of the body is:
Read answer →Physics · LAWS OF MOTION
A ball is released from rest at a height \( h = 0.45\text{ m} \) on a smooth inclined plane 1 inclined at \( 30^\circ \) to the horizontal. After reaching the bottom, it travels up a smooth inclined plane 2 for which \( \sin\theta_2 = \frac{1}{3} \). Assuming \( g = 10\text{ m/s}^2 \), what is the total time taken by the ball from release until it comes to instantaneous rest on plane 2?
Read answer →Physics · LAWS OF MOTION
Two identical balls strike a rigid wall with the same speed \( u \). Ball A hits normally, while Ball B hits at an angle of \( 30^\circ \) with the normal and reflects at the same angle without change in speed. The ratio of the magnitudes of impulse imparted to Ball A and Ball B is:
Read answer →Physics · LAWS OF MOTION
An impulse of \( 15 \text{ N s} \) is applied to a body of mass \( 3 \text{ kg} \) initially at rest. The final velocity acquired by the body is:
Read answer →Physics · LAWS OF MOTION
A time-dependent force \( F(t) = (12t^2 - 6t)\text{ N} \) acts on a particle of mass \( m = 0.5\text{ kg} \). If the particle starts from rest at \( t = 0\text{ s} \), calculate its velocity at \( t = 2\text{ s} \) and the total work done by this force on the particle during the time interval from \( t = 0\text{ s} \) to \( t = 2\text{ s} \).
Read answer →Physics · LAWS OF MOTION
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): A body can move along a straight line with uniform velocity only when a non-zero net external force acts continuously on it. Reason (R): According to Newton's First Law of Motion, if the net external force acting on a body is zero, its acceleration is zero and it continues to move with uniform velocity if already in motion. In the light of the above statements, choose the correct answer from the options given below:
Read answer →Physics · LAWS OF MOTION
Refer to the given figure showing a book resting on a horizontal table. The weight of the book is \( W \) downward and the normal force exerted by the table is \( R \) upward. What is the net force acting on the book?
Read answer →Physics · LAWS OF MOTION
A car is traveling along a straight horizontal road at a constant speed \( v = 20\text{ m/s} \). A box of mass \( m = 20\text{ kg} \) rests on the flat horizontal floor of the car. The coefficient of static friction between the box and floor is \( \mu_s = 0.4 \). Taking \( g = 10\text{ m/s}^2 \), the minimum stopping distance over which the car can be stopped with constant retardation without causing the box to slide is:
Read answer →Physics · LAWS OF MOTION
A heavy sphere of mass \( 8\text{ kg} \) is suspended in equilibrium by two light inextensible strings attached to rigid ceiling supports. One string makes an angle of \( 30^\circ \) with the vertical, while the other string makes an angle of \( 60^\circ \) with the vertical. Taking \( g = 10\text{ m/s}^2 \), the tension in the string making an angle of \( 30^\circ \) with the vertical is:
Read answer →Physics · LAWS OF MOTION
